Conventional illuminating lamps generally employ light emitting diode (LED) dies as light sources. However, water vapor has an adverse effect on the LED die, so that the LED die under extended or long duration contact with water vapor is damaged easily, thereby shortening the lifetime/lifespan of the LED die. Consequently, the present LED dies are always encapsulated to insulate the LED die from external water vapor. Moreover, the LED dies in some of the illuminating lamps, such as the lamp on fishing boat, which works in humid environments need good encapsulations to prevent the invasion of water vapor effectively.